This project is designed to study the biosynthesis of two quantitatively important red cell membrane proteins - band 3, and integral membrane glycoprotein, and spectrin, a superficial membrane protein bound to the inner surface of the red cell membrane. These proteins were selected because they appear to be typical members of these two general classes of membrane proteins. Anti-sera have been raised in guinea pigs to both proteins with which we hope to be able to selectively precipitate out both proteins from a mixture of newly synthesized proteins. Using these antibodies and a double-antibody precipitation method, we plan to study the biosynthesis of these two membrane proteins in cell-free lysates prepared from bone marrow cells of anemic rabbits. Eventually we plan to localize the type of ribosomes responsible for the synthesis of each protein and to determine the mechanism by which each is incorporated into the cell membrane.